Enhanced delivery of fixed-dose combination of synergistic antichagasic agents posaconazole-benznidazole based on amorphous solid dispersions

Stability Challenges of Amorphous Solid Dispersions of Drugs: A Critical Review on Mechanistic Aspects

The most common drawback of the existing and novel drug molecules is their low bioavailability because of their low solubility. One of the most important approaches to enhance the bioavailability in the enteral route for poorly hydrophilic molecules is amorphous solid dispersion (ASD). The solubility of compounds in amorphous form is comparatively high because of the availability of free energy produced during formulation. This free energy results in the change of crystalline nature of the prepared ASD to the stable crystalline form leading to the reduced solubility of the product. Due to the intrinsic chemical and physical uncertainty and the restricted knowledge about the interactions of active molecules with the carriers making, this ASD is a challenging task. This review focused on strategies to stabilize ASD by considering the various theories explaining the free-energy concept, physical interactions, and thermal properties. This review also highlighted molecular modeling and machine learning computational advancement to stabilize ASD.

Molecular complexes of drug combinations: A review of cocrystals, salts, coamorphous systems and amorphous solid dispersions

As the advancements in the medical technology and healthcare develop through the years, combinational therapy has evolved to be an important treatment modality in many disease settings, including cancer, cardiovascular disease and infectious diseases. In an effort to alleviate "pill burden" and improve patient compliance, fixed dose combinations (FDCs) have been developed to be used as effective therapeutics. Among all FDCs, the category of drug-drug molecular complexes has been proven an efficient methodology in designing and treating diseases, with many drugs being approved. Among all drug-drug molecular complexes, drug-drug cocrystals, salts, coamorphous systems and solid dispersions have been successfully developed and many have been approved by the FDA. In this review, we dwell deeply into the molecular mechanisms behind the different types of drug-drug molecular complexes, including the key functional groups involved in the intermolecular interactions, the applications of each category of molecular complexes, as well as the advantages and challenges thereof. This comprehensive review provides useful insights into the practical design and manufacture of drug-drug molecular complexes and points out the future direction for the development of new advantageous combinational therapies that benefit more patients.

pH-responsive phthalate cashew gum nanoparticles for improving drugs delivery and anti-Trypanosoma cruzi efficacy

Nanotechnology is a crucial technology in recent years has resulted in new and creative applications of nanomedicine. Polymeric nanoparticles have increasing demands in pharmaceutical applications and require high reproducibility, homogeneity, and control over their properties. Work explores the use of cashew phthalate gum (PCG) as a particle-forming polymer. PCG exhibited a pH-sensitive behavior due to the of acid groups on its chains, and control drug release. We report the development of nanoparticles carrying benznidazole. Formulations were characterized by DLS, encapsulation efficiency, drug loading, FTIR, pH-responsive behavior, release, and in vitro kinetics. Interaction between polymer and drug was an evaluated by molecular dynamics. Morphology was observed by SEM, and in vitro cytotoxicity by MTT assay. Trypanocidal effect for epimastigote and trypomastigote forms was also evaluated. NPs responded to the slightly basic pH, triggering the release of BNZ. In acidic medium, they presented small size, spherical shape, and good stability. It was indicated NP with enhanced biological activity, reduced cytotoxicity, high anti T. cruzi performance, and pH-sensitive release. This work investigated properties related to the development and enhancement of nanoparticles. PCG has specific physicochemical properties that make it a promising alternative to drug delivery, however, there are still challenges to be overcome.

Continuous Manufacturing and Molecular Modeling of Pharmaceutical Amorphous Solid Dispersions

Amorphous solid dispersions enhance solubility and oral bioavailability of poorly water-soluble drugs. The escalating number of drugs with poor aqueous solubility, poor dissolution, and poor oral bioavailability is an unresolved problem that requires adequate interventions. This review article highlights recent solubility and bioavailability enhancement advances using amorphous solid dispersions (ASDs). The review also highlights the mechanism of enhanced dissolution and the challenges faced by ASD-based products, such as stability and scale-up. The role of process analytical technology (PAT) supporting continuous manufacturing is highlighted. Accurately predicting interactions between the drug and polymeric carrier requires long experimental screening methods, and this is a space where computational tools hold significant potential. Recent advancements in data science, computational tools, and easy access to high-end computation power are set to accelerate ASD-based research. Hence, particular emphasis has been given to molecular modeling techniques that can address some of the unsolved questions related to ASDs. With the advancement in PAT tools and artificial intelligence, there is an increasing interest in the continuous manufacturing of pharmaceuticals. ASDs are a suitable option for continuous manufacturing, as production of a drug product from an ASD by direct compression is a reality, where the addition of multiple excipients is easy to avoid. Significant attention is necessary for ongoing clinical studies based on ASDs, which is paving the way for the approval of many new ASDs and their introduction into the market.

Solid Nanomedicines of Nifurtimox and Benznidazole for the Oral Treatment of Chagas Disease

Chagas disease (CD) is a parasitic zoonosis endemic in Central and South America affecting nearly 10 million people, with 100 million people at high risk of contracting the disease. Treatment is only effective when received at the early stages of the disease and it involved two drugs (nifurtimox (NFX) and benznidazole (BNZ)). Both treatments require multiple daily administrations of high doses, suffer from variable efficacy and insufficient efficacy in chronic CD, many side effects, and a very long duration of treatment that results in poor compliance, while combined available therapies that lead to reduced duration of treatment are not available and polypharmacy reduces compliance and increases the cost further. Here we present self-nanoemulsified drug delivery systems (SNEDDS) able to produce easily scalable combined formulations of NFX and BNZ that can allow for tailoring of the dose and can be easily converted to oral solid dosage form by impregnation on mesoporous silica particles. SNEDDS demonstrated an enhanced solubilisation capacity for both drugs as demonstrated by flow-through studies and in vitro lipolysis studies. High loading of SNEDDS to Syloid 244 and 3050 silicas (2:1 w/w) allowed clinically translatable amounts of both NFX and BNZ to be loaded. Tablets prepared from NFX-BNZ combined SNEDDS loaded on Syloid 3050 silicas demonstration near complete dissolution in the flow through cell apparatus compared to NFX and BNZ commercial tablets respectively (Lampit^® and Rochagan^®). NFX-BNZ-SNEDDS demonstrated nanomolar efficacy in epimastigotes and amastigotes of T. cruzi with acceptable selectivity indexes and demonstrated enhanced survival and reduced parasitaemia in acute murine experimental models of CD. Thus, the results presented here illustrate the ability for an easily scalable and personalised combination oral therapy prepared from GRAS excipients, enabling treatment access worldwide for the treatment of CD.

Drug associations as alternative and complementary therapy for neglected tropical diseases

The present paper aims to establish different treatments for neglected tropical disease by a survey on drug conjugations and possible fixed-dose combinations (FDC) used to obtain alternative, safer and more effective treatments. The source databases used were Science Direct and PubMed/Medline, in the intervals between 2015 and 2021 with the drugs key-words or diseases, like "schistosomiasis", "praziquantel", "malaria", "artesunate", "Chagas' disease", "benznidazole", "filariasis", diethylcarbamazine", "ivermectin", " albendazole". 118 works were the object of intense analysis, other articles and documents were used to increase the quality of the studies, such as consensuses for harmonizing therapeutics and historical articles. As a result, an effective NTD control can be achieved when different public health approaches are combined with interventions guided by the epidemiology of each location and the availability of appropriate measures to detect, prevent and control disease. It was also possible to verify that the FDCs promote a simplification of the therapeutic regimen, which promotes better patient compliance and enables a reduction in the development of parasitic resistance, requiring further studies aimed at resistant strains, since the combined APIs usually act by different mechanisms or at different target sites. In addition to eliminating the process of developing a new drug based on the identification and validation of active compounds, which is a complex, long process and requires a strong long-term investment, other advantages that FDCs have are related to productive gain and gain from the industrial plant, which can favor and encourage the R&D of new FDCs not only for NTDs but also for other diseases that require the use of more than one drug.

Explicating the molecular level drug-polymer interactions at the interface of supersaturated solution of the model drug: Albendazole

Supersaturation as a formulation principle relates to the aqueous solubility of poorly soluble drugs in solution . However, supersaturation state of drugs tends to crystallize because of its thermodynamic instability thereby compromising the solubility and biopharmaceutical performance of drugs. The present study aims to investigate the supersaturation potential of albendazole (ABZ) and its precipitation via nucleation and crystal growth. We hypothesized the use of polymers will avoid ABZ precipitation by interacting with drug molecules. The drug polymer interactions are characterized using conventional methods of Fourier transform infrared (FTIR), Nuclear magnetic resonance (NMR) and Polarized light microscopy (PLM). We have used a novel approach of sum frequency generation (SFG) vibrational spectroscopic in exploring the drug polymer interactions at air-water interface. Recently we have reported the SFG for e rifaximin-polymer interactions (Singh et al., 2021). The supersaturation assay, saturation solubility studies and nucleation induction time analysis revealed polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP K30) as effective precipitation inhibitors thereby enhancing the ABZ equilibrium solubility and in vitro supersaturation maintenance of ABZ. Further, modification in the solid state of ABZ has confirmed the influence of polymers on its precipitation behaviour. We conclude that PVA and PVP K30 act as nucleation and crystal growth inhibitor, respectively for the precipitation inhibition of ABZ.

Maximizing the Oral Bioavailability of Poorly Water-Soluble Drugs Using Novel Oil-Like Materials in Lipid-Based Formulations

Lipid-based formulations, such as self-microemulsifying drug-delivery systems (SMEDDSs), are promising tools for the oral delivery of poorly water-soluble drugs. However, failure to maintain adequate aqueous solubility after coming into contact with gastrointestinal fluids is a major drawback. In this study, we examined the use of a novel cinnamic acid-derived oil-like material (CAOM) that binds drugs with a high affinity through π-π stacking and hydrophobic interactions, as an oil core in a SMEDDS for the oral delivery of fenofibrate in rats. The use of the CAOM in the SMEDDS resulted in an unprecedented enhancement in fenofibrate bioavailability, which exceeded the bioavailability values obtained using SMEDDSs based on corn oil, a conventional triglyceride oil, or Labrasol, an enhancer of intestinal permeation. Further characterization revealed that the CAOM SMEDDS does not alter the intestinal permeability and has no inhibitory activity on P-glycoprotein-mediated drug efflux. The results reported herein demonstrate the strong potential of CAOM formulations as new solubilizers for the efficient and safe oral delivery of drugs that have limited water solubility.

Cocrystal of Apixaban-Quercetin: Improving Solubility and Bioavailability of Drug Combination of Two Poorly Soluble Drugs

Drug combinations have been the hotspot of the pharmaceutical industry, but the promising applications are limited by the unmet solubility and low bioavailability. In this work, novel cocrystals, consisting of two antithrombotic drugs with poor solubility and low bioavailability in vivo, namely, apixaban (Apx) and quercetin (Que), were developed to discover a potential method to improve the poor solubility and internal absorption of the drug combination. Compared with Apx, the dissolution behavior of Apx–Que (1:1) and Apx–Que–2ACN (1:1:2) was enhanced significantly, while the physical mixture of the chemicals failed to exhibit the advantages. The dissolution improvements of Apx–Que–2ACN could be explained by the fact that the solid dispersion-like structure and column-shaped cage of Que accelerated the access of the solvent to the inner layer of Apx. The fracture of the hydrogen bonds of Apx, which was the joint of the adjacent Que chains, facilitated the break-up of the structures. Besides, the bioavailability of Apx–Que was increased compared with the physical mixture and Apx, and Apx–Que remained stable in high temperature and illumination conditions. Therefore, a drug–drug cocrystal of two antithrombotic agents with poor solubility was developed, which exhibited greatly improved solubility, bioavailability and superior stability, indicating a novel method to overcome the shortages of drug combination.

Novel Solid Dispersions of Naphthoquinone Using Different Polymers for Improvement of Antichagasic Activity

IVS320 (3a,10b-dihydro-1H-cyclopenta[b]naphtho[2,3-d]furan-5,10-dione) is a naphthoquinone that has low solubility in aqueous medium, a physical behavior that limits its biological activities, considering that compounds from this class have several activities. In this work, solid dispersions (SDs) prepared between IVS320 and polymers hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG), and polyvinylpyrrolidone (PVP) were developed using physical mixture (PM), kneading (KN), and rotary evaporation (RE) methods. Dispersions were investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). In addition, in vitro antiparasitic activity in Trypanosoma cruzi Y strains was evaluated. Physical-chemical characterization demonstrated the formation of SDs through the interaction of IVS320 with polymeric matrices. SDs of IVS320-polymer presented a significant potentiation of antichagasic activity, with inhibitory growth around 62% (IVS320-HPMC/RE), 55% (IVS320-PEG/RE), and 85% (IVS320-PVP/RE), while pure IVS320 showed a value of 48% for the highest concentrations evaluated (50 µg/mL).

Application of HPMC HME polymer as hot melt extrusion carrier in carbamazepine solid dispersion

AIM

This work is to investigate the application characteristics of a new hot melt extrusion (HME) polymer (HME-grade hydroxypropyl methylcellulose, namely HPMC HME 15LV) in solid dispersion by HME.

METHODS

Carbamazepine (CBZ) was chosen as the model drug. And two types of solid dispersion system was prepared by HME, that is, single carrier system which was composed of PVP VA64(VA64) or Soluplus (SOL), and binary carrier which was composed of HPMC HME 15LV and SOL. Phase analysis of the extrudates were characterized by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). The dissolution, moisture absorption and thermal stability CBZ solid dispersion (CBZ-SD) were also investigated. In addition, the mechanism that affects the capsule dissolution was evaluated by the viscosity test and infiltration capability test.

RESULTS

CBZ-SD was prepared by HME. DSC and PXRD results indicated that CBZ was amorphous in all solid dispersions. Unlike CBZ-SD powder with high dissolution, CBZ-SD capsules showed the variable gelatinization phenomenon during dissolution and different dissolution behaviors, which can be interpreted by the viscosity test and infiltration capacity test. Furthermore, compared with single carrier system, CBZ-SD made by binary carrier exhibited lower moisture absorption and better thermal stability, which is benefit to the long-term stability of CBZ-SD.

CONCLUSION

HPMC HME 15LV, as a new HME carrier, has certain advantages in producing well CBZ-SD preparation. Its low viscosity can prevent the gelatinization phenomenon during capsule dissolution, as well as suitable T_g and low hygroscopicity were also benefit to the stability of CBZ-SD.

Obtaining and Applying Nanohybrid Palygorskite-Rifampicin in the pH-Responsive Release of the Tuberculostatic Drug

Despite having good efficacy in the treatment and prevention of tuberculosis, the administration of rifampicin (RIF) can cause serious side effects, resulting from the prolonged use of this substance. Thus, it is necessary to seek new systems for administering tuberculostatic drugs, to avoid unwanted adverse effects, increase their bioavailability and, consequently, improve their therapeutic efficacy. The present work describes the achievement of a pH-responsive system for RIF, using palygorskite, a fibrous clay mineral, as a nanocarrier. To evaluate the influence of some operational variables on the drug adsorption process, a 2⁴ factorial experimental design was used. The experiment using a maximum concentration (0.125 mg/mL), lower mass of PAL (300 mg), and lower pH (pH 2) was more efficient compared to other experiments, resulting in a higher dose of the incorporated drug, equivalent to 33.62 mg/g. To elucidate the mechanism of interaction between the materials, the hybrid obtained was characterized by different characterization techniques (Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry/derived thermogravimetry, zeta potential, scanning electron microscopy, and dispersive energy spectroscopy). In addition, kinetic models and adsorption isotherms were applied to the experimental data. Through in vitro release studies, it was possible to verify the effectiveness of the pH-dependent system obtained. The adjustment of experimental release data to the theoretical model of Higuchi indicated that the release of rifampicin occurs in a prolonged way from the palygorskite.

Nanocarriers for effective delivery of benznidazole and nifurtimox in the treatment of chagas disease: A review

Neglected tropical diseases (NTDs) constitute a group of infectious diseases prevalent in countries with tropical and subtropical climate that affect the poorest individuals and produce high chronic disability associated with serious problems for the health system and socioeconomic development. Chagas disease or American trypanosomiasis is included on the NTDs list. However, even though this disease affects more than 10 million people, mostly in Latin America, causing the death of over 10,000 people every year, only two drugs are approved for its treatment, benznidazole and nifurtimox. These antiparasitic agents were developed almost half a century ago and present several biopharmaceutical disadvantages such as low aqueous solubility and permeability limiting their bioavailability. In addition, both therapeutic agents are available only as tablets and a liquid pediatric formulation is still lacking. Therefore, novel pharmaceutical strategies to optimize the pharmacotherapy of Chagas disease are urgently required. In this regard, nanotechnological approaches may be a crucial alternative for the delivery of both drugs ensuring an effective pharmacotherapy although the successful bench-to-bedside translation remains a major challenge. The present work reviews in detail the formulation and in-vitro/in-vivo analysis of different nanoformulations of nifurtimox and benznidazole in order to enhance their solubility, dissolution, bioavailability and trypanocidal activity.

Solid dispersion technology as a strategy to improve the bioavailability of poorly soluble drugs

Over the last half-century, solid dispersions (SDs) have been intensively investigated as a strategy to improve drugs solubility and dissolution rate, enhancing oral bioavailability. In this review, an overview of the state of the art of SDs technology is presented, focusing on their classification, the main preparation methods, the limitations associated with their instability, and the marketed products. To fully take advantage of SDs potential, an improvement in their physical stability and the ability to prolong the supersaturation of the drug in gastrointestinal fluids is required, as well as a better scientific understanding of scale-up for defining a robust manufacturing process. Taking these limitations into account will contribute to increase the number of marketed pharmaceutical products based on SD technology.

Combining amorphous solid dispersions for improved kinetic solubility of posaconazole simultaneously released from soluble PVP/VA64 and an insoluble ammonio methacrylate copolymer

The aim of this study was to evaluate the potential of combining multiple ASDs based on water soluble and insoluble polymers to reach and maintain poorly soluble posaconazole (PCZ) supersaturation over time. ASDs of PCZ were obtained with PVP/VA64 or an ammonio methacrylate copolymer by solvent evaporation method with a fixed 20% (wt/wt%) drug loading ratio and physical mixtures of these ASDs were prepared at various proportions. ASDs were characterized by Fourier transform infrared spectroscopy (FT-IR) and powder X-ray diffraction (PXRD) and compared to their respective physical mixture with crystalline PCZ. Crystalline PCZ equilibrium solubility was determined at pH 1.2-2 range. Dissolution profiles were constructed under non-sink condition with an adapted dissolution system. PXRD analysis demonstrated that both ASDs were at the amorphous state and FT-IR spectroscopy revealed that the analytical signal of PCZ was also absent in both ASDs. Equilibrium solubility of crystalline PCZ varied between 26.36 ± 0.32 (pH 2) to 609.33 ± 3.68 (pH 1.2) μg/mL. All ASDs reached higher concentrations than the equilibrium solubility of crystalline PCZ during dissolution. PVP/VA64 ASDs showed dominance over PCZ dissolution and recrystallization rates whereas Eudragit RS PO ASD alone did not cause PCZ recrystallization whatsoever. The combination containing 20 mg PVP/VA64 + 80 mg Eudragit RS PO as PCZ carriers obtained the highest AUC, suggesting that even after the PVP/VA64 part was completely dissolved, reaching a concentration above crystalline PC C_s, the insoluble polymer could still release PCZ slowly and maintain supersaturation over time. The research demonstrated a potential of combining multiple ASDs to achieve distinct dissolution profiles while increasing the kinetic solubility of poorly soluble drugs.

Development and characterization of benznidazole nano- and microparticles: A new tool for pediatric treatment of Chagas disease?

Benznidazole (BNZ) is the drug of choice for the treatment of Chagas disease in many countries. However, its low water solubility produces low and/or variable oral bioavailability. Thus, the aim of this work was to formulate micro- and nanoparticles based on Eudragit^® RS PO and Eudragit^® RL PO as a convenient approach to increase the dissolution rate of BNZ. The microparticles were obtained by means of spray-drying process while the nanoparticles were prepared through the nanoprecipitation technique and further freeze-drying. The results indicated that nanoparticles were obtained in 86% yield while microparticles were obtained in 68% yield. In both cases, the encapsulation efficiency of particles was greater than 78% while drug loading capacity was nearly 24% w/w and 18% w/w, after spray-drying and freeze-drying procedures, respectively. Images of scanning electron microscopy showed that the particles obtained by spray-drying and freeze-drying were in the micrometer and nanometer scale, respectively. FT-IR spectra of BNZ-loaded particles obtained by both methods showed characteristic bands of BNZ confirming that part of drug remained on their surface. Thermal analysis revealed that the drug crystallinity after both methods decreased. Physical stability evaluation of the nanoparticles confirmed that Pluronic^® F68 was suitable to keep the particles size in a range of 300 nm after 70 days storage at 4 ± 2 °C. In-vitro release studies showed increased dissolution rate of drug from the particles obtained by both methods respect to untreated BNZ. The kinetics of drug release in acid media followed the Higuchi kinetics indicating drug diffusion mechanism from particles.

Stabilizing supersaturated drug-delivery system through mechanism of nucleation and crystal growth inhibition of drugs

A supersaturated drug-delivery system is capable of enhancing oral bioavailability of hydrophobic drugs. Maintenance of the supersaturated system both in vitro and in vivo is one of the most challenging parts, for that it is required to keenly understand the nucleation and crystal growth behavior. Polymers are widely used to stabilize supersaturated solutions; screening of polymers is done on the basis of their interaction with drug. Nucleation and crystal growth inhibition and drug–polymer interactions can be investigated by using various spectroscopic methods. Various formulations are prepared as supersaturated systems using different drug-delivery systems utilizing different polymers, which illustrates that supersaturation is worthwhile to increase the solubility and hence oral bioavailability of poorly soluble drugs.